This invention relates to a printer for multi-color silk screen printing.
In the printing of fabrics, such as T-shirts, caps and the like, multiple silk screens are used for the application of various colors to form a composite print. The printer generally comprises a stand and secured to the stand are pallets on which are secured the articles to be printed. The article is usually secured to the pallet with clamps or a hold down unit. The pallet, or each pallet when more than one is used, defines a station. The pallet may or may not be adapted for rotation about the stand.
Rotatively secured to the stand, above and spaced apart from the pallets, are a plurality of printing heads arranged in a carrousel-like configuration. The heads rotate and each head will automatically lock into position in register with a pallet.
Generally the head comprises a frame and a silk screen received in the frame with clamps to secure the silk screen. Additionally, the heads are biased in an upper position such as by springs, pneumatic devices and the like. Clamps, bolts, screws and the like are used to fine-tune or micro-adjust each silk screen. This adjustment is to ensure registration of the successive applications of the silk screen to the fabric to be printed. As is well understood, each silk screen embodies a different portion of the total design and each normally applies a different color.
In the commercially available units, there are modular units whereby one to four colors may be applied with a single printer. However, when more colors are to be applied, a more expensive printer is required and generally six and eight color printers are sold separately. Further, the micro-registration systems commonly used in these printers adjust the clamps which secure the screens.
It would be desirable if a printer could be provided which could be used to print one, two, three, four, five, six, seven or eight or any combination of colors by the simple addition of pallets and heads to a basic printing unit. Further, it would be advantageous if a micro-adjust system were available which functioned independently of the clamping mechanisms which holds the silk screen and additionally could adjust the screen along several directions.
Basically the invention comprises a printer which comprises a base structure to which may be secured any combination of pallets and printing heads. The heads are carried on arms. The anchor plates which hold these arms to the base are each adjustable to ensure these arms are parallel with the arm carrying the pallet. The arm carrying the head is also adjustable along its longitudinal axis. Positioning bars are secured between pallet arms and an alignment shaft is secured to each pallet arm. An orifice is provided in the adjustable portion of the arm carrying the head. This orifice receives the alignment shaft during printing to ensure registration and locking of the arms.
In another aspect of the invention, the assembly holding the silk screen is adjustable along the perpendicular X, Y and Z axes, and can sidle adjust along the Z axis.